# Gantry Alignment Issue during EX Controller and Server Motor Upgrade

**URL:** <https://forum.avidcnc.com/t/gantry-alignment-issue-during-ex-controller-and-server-motor-upgrade/5300>\
**Category:** Build Logs\
**Created:** [September 26, 2025, 11:12pm UTC](https://forum.avidcnc.com/t/gantry-alignment-issue-during-ex-controller-and-server-motor-upgrade/5300 "2025-09-26T23:12:35Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Dewey98](https://avatars.discourse-cdn.com/v4/letter/d/c5a1d2/32.png) [@Dewey98](https://forum.avidcnc.com/u/Dewey98)\
**Post date:** [September 26, 2025, 11:12pm UTC](https://forum.avidcnc.com/t/gantry-alignment-issue-during-ex-controller-and-server-motor-upgrade/5300/1 "2025-09-26T23:12:35Z")

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Hello AVID enthusiasts. I started the upgrade of my PRO CNC, but I didn’t get far on the EX upgrade before I ran into an issue I need to correct. I found this after I disengaged the motors from the rails by loosening the tension bolts on both sides.  
I only got up to step “2.3 - Align Bumper Plates” step and the gantry is not aligned. When the Gantry is pulled all the way forward the left side is measured at 12.38mm and the right side is at 9.28mm, the difference in spacing between the two blue lines in the picture, (2.4 - Sensor Screw Adjustment).  
If the table is square how do you align this so the distances are the same? Did it get out of alignment when I loosened the tension bolts?

 ![Gantry-Alignment](https://canada1.discourse-cdn.com/flex027/uploads/avidcnc/original/2X/8/895d9af9be0ad0a2fdda7eb8fdcd0a49c553152e.jpeg)

It’s hard to make the measurements when the “Rack and Pinion” drives are not engaged.  
How do I correct this? Do I correct it with the Rack & Pinions engaged or disengaged?  
Thank you for any assistance, I hope I can move forward this weekend.

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**Author:** ![Eric](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.avidcnc.com/eric/32/3220_2.png) [@Eric](https://forum.avidcnc.com/u/Eric)\
**Post date:** [September 27, 2025, 2:50am UTC](https://forum.avidcnc.com/t/gantry-alignment-issue-during-ex-controller-and-server-motor-upgrade/5300/2 "2025-09-27T02:50:56Z")

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Just pull the gantry tight to the bumper. You can use a clamp.

[![](https://canada1.discourse-cdn.com/flex027/uploads/avidcnc/original/2X/8/836fd112ebe0dc563be87764e83e94ebe367b011.jpeg "Squaring your Avid CNC Machine") ](https://www.youtube.com/watch?v=qz6VrsEq_Xc)